Provincetown, Mass. (CBS Boston/CBS Local) — Passengers on board a whale watching boat off Cape Cod were treated to a rare sight last week. The Hyannis Whale Watcher boat was about a mile and a half north of Race Point when it came upon a snake swimming in the ocean.

According to Joanne Jarzobski, a marine biologist for Hyannis Whale Watcher Cruises, the snake was an eastern hognose snake. These snakes thrive in sandy habitats on the Cape.

In her five years with the company, Jarzobski has never a snake swimming on the job — or during her decades of prior work in the Atlantic Ocean for that matter.

While it is very rare to see an eastern hognose go swimming, it’s not unprecedented, she confirmed. All least four sightings have been recorded over the last century.

Jarzobski and the crew debated helping the snake to shore because it was likely disoriented or had been taken up by the current. They then decided the whale watching boat sat too high above the water for them to do anything.